It is possible that the main title of the report Marfan Syndrome is not the name you expected. Please check the synonyms listing to find the alternate name(s) and disorder subdivision(s) covered by this report.
As Jenny points out, being able to lisp the alphabet song at age two has little to do with 'knowing' the alphabet. And, yes, most children learn the letters by sight and sound in kindergarten, although most are capable of learning this information sooner if diligently taught by parents or others.
Read to your child. Play rhyming games. Sing the alphabet song with them. Label things with their names from an early age. Go to the library even when they are at that loud voice only stage. Have nonfiction books as well as fiction available . Tell stories. Have books all over your house.